Where to place the API key in the gatsby-pwa-demo site?

I am following the instructions for building out the gatsby-pwa-demo site, which states, " To install Snipcart on your website, copy the following HTML code snippet and paste it directly into your website’s markup. As a best practice, we recommend you add it directly after the <body> element.

I cannot find the element anywhere. Should I put the API snippet in gastby-browser.js or should I create a file for the snippet or other?

I tried putting the API snippet in gatsby-browswer.js and errors surfaced.